Field of the Invention
The invention relates to a controller for the drive train of a motor vehicle (drive train controller).
In a known drive train controller, the transmission controller transmits, to the engine controller, a data element specifying the amount by which the (uncorrected) engine torque that is applied to the input shaft of the transmission is to be changed. In this context, this uncorrected engine torque is known to the transmission controller because the transmission controller either calculates the uncorrected engine torque itself or the uncorrected engine torque is transmitted to it by the engine controller via a communications line (See, for example, European Patent EP 0 518 855 B1). The transmission controller does not need to contain any engine-specific data in this context to convert a torque reduction into an ignition intervention, or into an intervention in the injection or the valve control. The conversion is carried out in the engine controller. As a result, the necessary variants of the transmission controller are considerably reduced.
In another modern drive train controller, only physically dimensioned descriptive variables that relate to the necessary engine torque reduction are exchanged between the transmission controller and the engine controller via an interface (See, For example, Published German Patent Application DE 197 27 044 A1). The transmission controller determines the behavior of the engine system on the basis of a generalized model. The model describes the behavior that is requested of the transmission controller at the limits of the engine/transmission system (engine output shaft) in a uniquely defined way without reference to the technical implementation in the engine system. The practical execution of an intervention in the engine is the sole responsibility of the engine controller. The engine controller defines whether an ignition intervention has to take place, whether the quantity of injected fuel is reduced, whether the valve control times or the valve characteristics have to be changed, or whether the engine is to be controlled by the throttle valve. The engine controller alone controls all of the actuators that are necessary for this. The dynamics of a change in the transmission ratio are not influenced in the known transmission and drive train controllers.
Published European Patent Application EP 0 719 996 A discloses a control method for the drive unit of a vehicle in which various operating parameters corresponding to the driving states are determined in a first stage. In a second stage, a first numerical value, which provides the gear speed with the lowest fuel consumption, and a second numerical value, which corresponds to the gear speed with the maximum power, are calculated. In a third stage, an optimized gear speed is defined on the basis of a function of the first and the second numerical value and in dependence on the operating parameters.
It is accordingly an object of the invention to provide a drive train controller which overcomes the above-mentioned disadvantages of the prior art apparatus of this general type.
In particular, it is an object of the invention to provide a transmission and a drive train controller that takes into account the dynamics of a change in the transmission ratio.
With the foregoing and other objects in view there is provided, in accordance with the invention, a drive train controller of a motor vehicle having an automatic transmission and an engine. The drive train controller includes: an engine controller for controlling variables that influence the torque of the engine; and a transmission controller for controlling gear shifting operations of the automatic transmission. The transmission controller exchanges data with the engine controller. This data enables the gear shifting operations to be performed comfortably. The drive train controller also includes a gear shift change controller for correcting a requested engine torque during a gear shifting operation. The transmission controller includes a detection circuit for determining a driving situation of the motor vehicle. The transmission controller adaptively matches changes in the transmission ratio to the dynamics of the driving situation that has been determined or the driver characteristics that have been determined.
In accordance with an added feature of the invention, a gear shift controller is provided that is embodied as a fuzzy logic circuit. The gear shift controller defines a gear shift strategy of a drive train of the motor vehicle.
In accordance with an additional feature of the invention, the detection circuit is a component of the gear shift controller.
In accordance with another feature of the invention, a clutch controller is provided that receives information from the gear shift controller. This information relates to a respective driving strategy and to the driving situation.
In accordance with a further feature of the invention, a line connects the gear shift change controller to the clutch controller to coordinate the clutch controller with a gear shift operation.
In accordance with a further added feature of the invention, a plurality of transmission actuators are connected to the gear shift change controller. The plurality of the transmission actuators are either electromechanical transmission actuators or electrohydraulic transmission actuators.
In accordance with a further additional feature of the invention, the gear shift change controller engages a new gear speed and synchronizes the transmission with low forces when changing from an idling position of the transmission into a driving position of the transmission.
In accordance with a yet an added feature of the invention, the gear shift controller executes a fuzzy logic program including: a first rule set that uses values selected from the group consisting of mean values of sensor signals and filtered values of sensor signals; and a second rule set for detecting rapid changes in a driving performance request.
The drive train controller of a motor vehicle having an engine and an automatic transmission is provided with an engine controller that controls the variables that influence the torque of the engine are controlled. The drive train controller is also provided with a transmission controller that controls the gear shift operations of the automatic transmission and that exchanges the data, which makes comfortable gear shift operations possible, with the engine controller. In this context, the transmission controller has a detection circuit that determines the respective driving situation of the motor vehicle. The transmission controller performs changes in the transmission ratio, which are adaptively matched to the determined driving situation.
The detection of driving situations is expediently carried out with a detection circuit that is embodied as a fuzzy logic circuit. Advanced transmission controls are frequently provided with fuzzy logic components (See, for example, F. Graf and H. Weil: Advanced Transmission with Fuzzy Logic, 3rd International Conference, Bologna, Mar. 29-31, 1995, Technical Papers pp. 379-389; and EP 0 576 703 A1) and can therefore easily be equipped with such a driving situation detection means. The advantages of the invention lie above all in the improvement in the driving comfort and in the driving safety of a motor vehicle in a wide range of driving situations. In the case of gear shift operations from a stationary state, for example, where there is a change from the idling of the transmission into a driving positionxe2x80x94or even in the case of gear shifts during slow driving, gear shift noises, which are otherwise usual and troublesome, are effectively avoided.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a controller for the drive train of a motor vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.